Method and apparatus of mutliplexing media streams

1. A method for generating a multiplex of media streams, the method comprising: receiving, by an interface, a set of media streams, each media stream of the set of media streams comprises non-encrypted media stream components and encrypted media stream components wherein the encrypted media stream components comprise encrypted video components; applying a modification process on the non-encrypted media stream components, so as to provide at least one modified non-encrypted media stream component; and multiplexing, by a multiplexing unit, at least the encrypted media stream components and the modified non-encrypted media stream components wherein the modifying process is selected from a group consisting of a lossy compression, a lossless compression, altering a size of at least one media stream component, and altering a timing of transmission of at least one media stream component; and wherein the modification process is not applicable to the encrypted video components.

2. The method of claim 1 wherein the modification process involves lossy compression.

3. The method of claim 1 wherein the modification process involves lossless compression.

4. The method of claim 1 wherein the modification process involves altering a size of at least one media stream component.

5. The method of claim 1 wherein the modification process involves altering a timing of transmission of at least one media stream component.

6. The method of claim 1 wherein the step of multiplexing further comprises multiplexing non-modified non-encrypted media stream components.

7. The method of claim 1 wherein the step of modifying comprises executing modification sessions in a periodical manner.

8. The method of claim 7 wherein each modification session is associated with a group of media stream components that are received during a certain time period.

9. The method of claim 7 wherein each modification session is associated with media stream components of a certain aggregate size.

10. The method of claim 7 wherein each modification session is associated with a group of media stream components to be transmitted during a certain time period.

11. The method of claim 7 wherein each modifications session is associated with media streams components of the set of media streams that were not transmitted.

12. The method of claim 7 wherein at least one modification session includes modifying a size of at least one media stream component of the group, evaluating the size of the at least one modified non-encrypted media stream component, and determining whether additional modification is required.

13. The method of claim 7 wherein at least one modification session includes modifying a timing of at least one media stream component of the group, evaluating the timing of the at least one modified non-encrypted media stream component, and determining whether additional modification is required.

14. The method of claim 11 wherein the additional modification comprises modifying a non-modified non-encrypted media stream component of the group or re-modifying a modified media stream component of the group.

15. The method of claim 1 wherein at least one media stream of the set is partially encrypted.

16. The method of claim 1 further comprising determining at least one control parameter.

17. The method of claim 16 wherein the determination is followed by selecting an encrypted version of a media stream out of multiple distinct encrypted versions.

18. The method of claim 17 wherein the distinct encrypted versions differ from each other by an encryption level.

19. The method of claim 17 wherein the distinct encrypted versions differ from each other by the manner that they were generated.

20. The method of claim 16 wherein the determination is followed by altering an encryption of a media stream.

21. The method of claim 16 wherein the determination is followed by altering the modification process.

22. The method of claim 16 further comprising assigning encryption priorities to media stream components and whereas encryption is altered in response to the at least one control parameter and the encryption priorities.

23. The method of claim 16 wherein a media stream is represented by multiple layers that are generated by a process that comprises quantizing the media stream by different quantization levels and whereas the determination is followed by altering at least one layer, deleting one layer or adding a new layer.

24. The method of claim 16 wherein a media stream is represented by multiple layers that are generated by a process that comprises quantizing the media stream by different quantization levels and whereas the determination is followed by altering the selection of layers that undergo encryption.

25. The method of claim 16 further comprising assigning modification priorities to media stream components and determining at least one control parameter in response to the modification priorities.

26. The method of claim 16 wherein the at least one control parameter is determined in response to the modification process.

27. The method of claim 16 wherein the at least one control parameter is determined in response to an encryption scheme applied on media stream components.

28. The method of claim 16 further comprising assigning encryption priorities to media stream components and determining at least one control parameter in response to the encryption priorities.

29. The method of claim 16 wherein the determination is responsive to the target bit rate, the bit rate of encrypted media stream components and of non-encrypted media stream components previously received.

30. The method of claim 16 wherein the determination is responsive to the timing and size associated with received media stream components.

31. The method of claim 1 wherein the step of modifying comprises selecting between encrypted media stream components and non-encrypted media stream components.

32. The method of claim 31 wherein the step of selecting comprises analyzing at least one encryption indication associated with at least one media stream component.

33. The method of claim 1 further comprising assigning modification priorities to media streams and modifying media stream components in response to the modification priorities.

34. The method of claim 1 wherein at least one media stream of the set is represented by multiple video layers and at least a portion of at least one layer is encrypted.

35. The method of claim 34 wherein the layers comprise a base layer and at least one supplemental layer, a supplemental layer for each pair of layers.

36. The method of claim 34 wherein the layers provide spatial scalability.

37. The method of claim 34 wherein the layers provide temporal scalability.

38. The method of claim 34 wherein the layers are generated by filtering.

39. An apparatus for generating a multiplex of media streams, the apparatus comprising: an interface, for receiving a set of media streams, each media stream of the set of media streams comprises non-encrypted media stream components and encrypted media stream components that comprise encrypted video components; a statistical multiplexing unit for applying a modification process on the non-encrypted media stream components, so as to provide at least one modified non encrypted media stream component wherein the modifying process is selected from a group consisting of a lossy compression, a lossless compression, altering a size of at least one media stream component, and altering a timing of transmission of at least one media stream component; wherein the modification process is not applicable to the encrypted video components, and for multiplexing at least the encrypted media stream components and the modified non-encrypted media stream components.

40. The apparatus of claim 39 wherein the modification process involves lossy compression.

41. The apparatus of claim 39 wherein the modification process involves lossless compression.

42. The apparatus of claim 39 wherein the modification process involves altering a size of at least one media stream component.

43. The apparatus of claim 39 wherein the modification process involves altering a timing of at least one media stream component.

44. The apparatus of claim 39 wherein the modification process involves altering a timing of transmission of at least one media stream component.

45. The apparatus of claim 39 wherein the statistical multiplexing unit is further adapted to multiplex non-modified non-encrypted media stream components.

46. The apparatus of claim 39 wherein statistical multiplexing unit is adapted to apply the modification process in modification sessions.

47. The apparatus of claim 46 wherein each modification session is associated with a group of media stream components that are received during a certain time period.

48. The apparatus of claim 46 wherein each modification session is associated with media stream components of a certain aggregate size.

49. The apparatus of claim 46 wherein each modification session is associated with a group of media stream components to be transmitted during a certain time period.

50. The apparatus of claim 46 wherein each modifications session is associated with media streams components of the set of media streams that were not transmitted.

51. The apparatus of claim 46 wherein at least one modification session includes modifying a size of at least one media stream component of the group, evaluating the size of the at least one modified non-encrypted media stream component, and determining whether additional modification is required.

52. The apparatus of claim 46 wherein at least one modification session includes modifying a timing of at least one media stream component of the group, evaluating the timing of the at least one modified non-encrypted media stream component, and determining whether additional modification is required.

53. The apparatus of claim 52 wherein the additional modification comprises modifying a non-modified non-encrypted media stream component of the group or remodifying a modified media stream component of the group.

54. The apparatus of claim 39 wherein at least one media stream of the set is partially encrypted.

55. The apparatus of claim 39 wherein the apparatus is further adapted to determine at least one control parameter.

56. The apparatus of claim 55 wherein the apparatus is adapted to select, in response to the determination, an encrypted version of a media stream out of multiple distinct encrypted versions.

57. The apparatus of claim 56 wherein the distinct encrypted versions differ from each other an encryption level.

58. The apparatus of claim 56 wherein the distinct encrypted versions differ from each other by the manner that they were generated.

59. The apparatus of claim 55 wherein apparatus is adapted to alter an encryption of a media stream in response to the determination.

60. The apparatus of claim 55 wherein the apparatus is adapted to alter the modification process in response to the determination.

61. The apparatus of claim 55 whereas encryption priorities are associated with media stream components and whereas the apparatus is adapted to alter the encryption in response to the at least one control parameter and the encryption priorities.

62. The apparatus of claim 55 wherein a media stream is represented by multiple layers that are generated by a process that comprises quantizing the media stream by different quantization levels and whereas the apparatus is adapted to alter at least one layer, delete one layer or add a new layer, in response to the determination.

63. The apparatus of claim 55 wherein a media stream is represented by multiple layers that are generated by a process that comprises quantizing the media stream by different quantization levels and whereas the determination is followed by altering the selection of layers that undergo encryption.

64. The apparatus of claim 55 wherein media stream components are associated with encryption priorities and wherein the determination of at least one control parameter is responsive to the encryption priorities.

65. The apparatus of claim 55 wherein media stream components are associated with modification priorities and wherein the determination of at least one control parameter is responsive-to the modification priorities.

66. The apparatus of claim 55 wherein the apparatus is adapted to determine at least one control parameter in response to an encryption scheme applied on media stream components.

67. The apparatus of claim 55 wherein the determination is responsive to the target bit rate, the bit rate of encrypted media stream components and of non-encrypted media stream components previously received.

68. The apparatus of claim 39 wherein the interface is capable of selecting between encrypted media stream components and non-encrypted media stream components.

69. The apparatus of claim 68 wherein interface is adapted to select in response to an analysis of at least one encryption indication associated with at least one media stream component.

70. The apparatus of claim 39 wherein media streams are associated with modification priorities to media streams and wherein the statistical multiplexing unit is adapted to modify media stream components in response to the modification priorities.

71. The apparatus of claim 39 wherein at least one media stream of the set is represented by multiple video layers and at least a portion of at least one layer is encrypted.

72. The apparatus of claim 71 wherein the layers comprise a base-layer and at least one supplemental layer, a supplemental layer for each pair of layers.

73. The apparatus of claim 71 wherein the layers provide spatial scalability.

74. The apparatus of claim 71 wherein the layers provide temporal scalability.

75. The apparatus of claim 71 wherein the layers are generated by various levels of filtering.

76. The method of claim 1 , wherein the applying of the modification process comprises modifying encrypted media stream components that are included in different media streams of the set of media streams.

77. The apparatus of claim 39 , wherein the statistical multiplexing unit is further adapted to modify encrypted media stream components that are included in different media streams of the set of media streams.

78. The method according to claim 1 , comprising generating by the modification process a feedback signal; and changing an encryption level of a media stream in response to the feedback signal.

79. The method according to claim 78 , wherein the media stream comprises encrypted audio components and non-encrypted video components and wherein the method comprises changing the encryption level by encrypting the encrypted audio components more extensively.

80. The method according to claim 78 , wherein the media stream comprises encrypted audio components and non-encrypted video components and wherein the method comprises changing the encryption level by encrypting the non-encrypted video components.

81. The method according to claim 78 , wherein the media stream is encrypted on a time division basis and wherein the method comprises changing the encryption level by encrypting lengthier portions of the media stream.

82. The method according to claim 78 , wherein the media stream comprises encrypted I-frames and non-encrypted B-frames and wherein the method comprises changing the encryption level by encrypting B-frames.

83. The apparatus according to claim 39 , arranged to generate a feedback signal; and to change an encryption level of a media stream in response to the feedback signal.